[X2Go-User] Session resume fails with AFS home directories

[Sebastian Flothow]

I did some further testing, and the resume failures are indeed due to 
missing AFS tokens. When suspending a session, the SSH connection is 
closed, sshd will call pam_close_session(), which means that pam_krb5 
and pam_afs_session will delete the user's ticket/token (resp.). The 
session therefore loses access to the home directory and appears to 
freeze up, preventing it from being resumed.

Both pam_krb5 and pam_afs_session accept retain_after_close as a 
parameter, which disables the delete-on-close behavior. With this 
parameter set, it becomes possible to resume sessions, unless the AFS 
token has expired.

This solves at least the case where the user reconnects quickly (eg. 
after a short network outage), but it still means sessions will become 
unresumable when left unused for a few days. I guess the only way to 
avoid this is to not store session data in the home directory. Can X2go 
be configured such that it uses eg. /tmp or /var/lib for this purpose?